Add complete ai.card Rust implementation

- Implement complete Rust API server with axum framework
- Add database abstraction supporting PostgreSQL and SQLite
- Implement comprehensive gacha system with probability calculations
- Add JWT authentication with atproto DID integration
- Create card master data system with rarities (Normal, Rare, SuperRare, Kira, Unique)
- Implement draw history tracking and collection management
- Add API endpoints for authentication, card drawing, and collection viewing
- Include database migrations for both PostgreSQL and SQLite
- Maintain full compatibility with Python API implementation
- Add comprehensive documentation and development guide

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Cargo.toml

@@ -0,0 +1,54 @@
+[package]
+name = "aicard"
+version = "0.1.0"
+edition = "2021"
+description = "ai.card API server - Rust implementation of autonomous card collection system"
+authors = ["syui"]
+
+[dependencies]
+# Core Web Framework
+axum = { version = "0.7", features = ["macros", "multipart"] }
+tokio = { version = "1.0", features = ["full"] }
+tower = { version = "0.4", features = ["full"] }
+tower-http = { version = "0.5", features = ["cors", "trace"] }
+
+# Database & ORM
+sqlx = { version = "0.7", features = ["runtime-tokio-rustls", "postgres", "sqlite", "uuid", "chrono", "migrate"] }
+uuid = { version = "1.0", features = ["v4", "serde"] }
+
+# Serialization & Validation
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+validator = { version = "0.18", features = ["derive"] }
+
+# Date/Time
+chrono = { version = "0.4", features = ["serde"] }
+
+# Authentication & Security
+jsonwebtoken = "9.0"
+bcrypt = "0.15"
+
+# HTTP Client (for atproto integration)
+reqwest = { version = "0.11", features = ["json"] }
+
+# Configuration
+config = "0.13"
+dotenvy = "0.15"
+
+# CLI
+clap = { version = "4.0", features = ["derive"] }
+
+# Random (for gacha system)
+rand = "0.8"
+
+# Error Handling
+anyhow = "1.0"
+thiserror = "1.0"
+
+# Logging
+tracing = "0.1"
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+
+# Development
+serde_yaml = "0.9"
+dirs = "5.0"